CHEM 30B Dr. R. Rinehart
Bases, Nucleosides, Nucleotides,
and Related Compounds

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Bases
They are called bases because of the N: that they contain

name

alternate names &
abbreviations

structure

comments

purine

pu




note the numbering

pyrimidine

py




note the numbering

adenine

A

6-aminopurine




in both DNA and RNA, base of ATP;
also in coenzymes like CoA, NAD+, FAD

cytosine

C
2-oxo-4-amino
pyrimidine




 

guanine

G

2-amino-6-oxo
purine




 

thymine

T

5-methyl-2,4-dioxo
pyrimidine




found “only” in DNA

uracil

U

2,4-dioxo
pyrimidine




found “only” in RNA

Base Pairs

T=A base pair




the sugars and backbone are not shown

the two hydrogen bonds are not shown either, but you should be able to tell where to draw them

A=T base pair




the sugars and backbone are not shown

the two hydrogen bonds are not shown either, but you should be able to tell where to draw them

C≡G base pair




the sugars and backbone are not shown

the three hydrogen bonds are not shown either, but you should be able to tell where to draw them

G≡C base pair




the sugars and backbone are not shown

the three hydrogen bonds are not shown either, but you should be able to tell where to draw them

Nucleosides

nucleosides consist of a heterocyclic base attached by a beta N-glycosidic linkage to a 5-C sugar, usually ribose or, for deoxynucleosides,  2-deoxyribose

name

alternate names &
abbreviations

structure

comments

adenosine

1’-b-

(9-adeninyl) riboside




 

adenosine is an inhibitory neurotransmitter in the central nervous system; its receptors are blocked by caffeine, producing CNS excitation.

cytidine

 




 

guanosine

 




 

thymidine

 




note that the sugar here  is 2’- deoxyribose; since thymine is found pretty much only in DNA, by convention the sugar it is shown attached to is always deoxyribose, but the "deoxy" is usually omitted from the name

uridine

 




 

AZT

3’-azido-3’-deoxythymidine

Zidovudine; Retrovir




used to treat HIV infections; an inhibitor of reverse transcriptase

ara-C

arabinosyl cytosine

cytarabine




used to treat leukemia and other cancers

idoxuridine

2’-deoxy-5-iodouridine

IdU




antiviral agent

Nucleotides
Nucleotides contain a phosphate ester group somewhere on the sugar of a nucleoside

name

alternate names &
abbreviations

structure

comments

adenosine 5’ monophosphate

AMP

adenylic acid

adenylate




an allosteric activator of glycolysis

adenosine 5’ diphosphate

ADP




the byproduct formed when ATP is hydrolyzed or has its terminal phosphate group transferred to another molecule;
an allosteric activator of glycolysis

adenosine 5’ triphosphate

ATP




See a Chime structure of ATP

a “high-energy” compound that is the major “energy currency” in living cells as well as a precursor for RNA synthesis

cytidine 5’ monophosphate

CMP

cytidylic acid

cytidylate




 

cytidine 5’ triphosphate

CTP




in addition to being a precursor for RNA synthesis, CTP is used in the synthesis of complex lipids

guanosine 5’ monophosphate

GMP

guanylic acid

guanylate




 

guanosine 5’ triphosphate

GTP




in addition to being a precursor for RNA synthesis, GTP is used as the energizer in the elongation phase of translation; it is also formed in the Krebs cycle.

thymidine 5’ monophosphate

dTMP

(deoxy) thymidylic acid

thymidylate




note that the sugar here  is 2’- deoxyribose; since thymine is found pretty much only in DNA, by convention the sugar it is shown attached to is always deoxyribose, but the "deoxy" is usually omitted from the name 

uridine 5’  monophosphate

UMP

uridylic acid

uridylate




 

uridine 5’  triphosphate

UTP




In addition to being a precursor for RNA synthesis, UTP is used as the energy source in glycogen synthesis, in the interconversion of glucose and galactose, and in the activation of glucuronic acid

cyclic 3’, 5’ adenosine monophosphate

cAMP

cyclic AMP




the intracellular  “second” messenger of a large number of hormones

cyclic 3’, 5’ guanosine monophosphate

cGMP

cyclic GMP




another important intracellular signalling agent

Nucleoside and Nucleotide Coenzymes

S-adenosyl methionine

SAM




methyl group donor in biosynthesis

flavin mononucleotide

FMN




hydrogen-accepting coenzyme

flavin-adenine dinucleotide

FAD




hydrogen-accepting coenzyme

nicotinamide-adenine dinucleotide

NAD+




hydrogen-accepting coenzyme

coenzyme A

CoA




acyl group carrier

© Ronald W. Rinehart, 2002  Structures Drawn with ACD Labs ChemSketch® and MDL IsisDraw®

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